Recently, interests in energy storage technology have been gradually increased. As the use of batteries is enlarged to applications for the storage of energy for portable telephones, camcorders, notebook computers, personal computers and electric vehicles, efforts on the research and development of batteries are increasingly embodied. In this view, the field of electrochemical devices receives the greatest attention, and among them, interests in the development of chargeable/dischargeable secondary batteries are focused. More recently, in the development of such batteries, active studies have been conducted to design a novel electrode and battery, which provide an improved capacity density and specific energy.
Among secondary batteries which are now in use, lithium secondary batteries developed in the early 1990s are in the spotlight due to the advantages of higher drive voltages and far greater energy densities than those of conventional batteries, such as Ni—MH, Ni—Cd and sulfuric acid-lead batteries. However, such lithium secondary batteries have a problem in that their quality is degraded during repeated charge/discharge cycles. The above problem becomes more serious as the drive/storage temperature of a battery increases. Therefore, there has been a continuous need for a method of improving high-temperature lifespan characteristics of a non-aqueous electrolyte lithium secondary battery.
Korean Laid-Open Patent No. 0450199 and US Patent No. 2002-0197537 disclose a method of improving lifespan characteristics and high-temperature characteristics of a battery by using a sulfonate-based compound represented by the following Formula 2 as an additive for electrolytes:

wherein R1 and R2 each represent an alkyl group, an alkenyl group or an aryl group.
Additionally, Japanese Laid-Open Patent No. 2000-13304 discloses that a compound represented by the following Formula 3 can improve lifespan characteristics and storage characteristics of a battery:

wherein R represents an alkyl group.
As described above, sulfonate (SO3)-based compounds have been already known to improve the quality of a battery when they are used as an additive for electrolytes.